Template:Info:Class-A-B description

This is a mixture of Class A and Class B amplifiers

Class A: has a large transistor that is on all the time. These amplifiers are linear but are not very power efficient, (can be as low as 30%) and will produce a lot of heat. That is, if you had a speaker driven at 30W power, in the worst case 70W of the amplifier power would be used WITHIN the amplifier, This energy is output as heat). Even if there is no signal, then there is a significant idling power.

Class B: has two large transistors in a push-pull setup. These are more efficient, typically 50-60%, but not as linear and produce zero-crossing distortion.

Class A-B combines these classes but keeps a more efficient power handling, typically 50-60% efficient, and adds a bias to remove the zero-crossing distortion and keep a linear signal.

In Linn amplifiers this is typically the amplifier negative is tied to ground/earth and only the positive terminal changes voltage.

In other words:

Class A: Sounds good, but uses a lot of power all the time

Class B: Sounds OK, but doesn't use much less power than Class-A.

Class A-B: Sounds good and doesn't break the bank on Electricity/power bills.